Connected: An Internet Encyclopedia
RFC 1812 - 2.2.4 Autonomous Systems

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### 2.2.4 Autonomous Systems

An Autonomous System (AS) is a connected segment of a network topology that consists of a collection of subnetworks (with hosts attached) interconnected by a set of routes. The subnetworks and the routers are expected to be under the control of a single operations and maintenance (O&M) organization. Within an AS routers may use one or more interior routing protocols, and sometimes several sets of metrics. An AS is expected to present to other ASs an appearence of a coherent interior routing plan, and a consistent picture of the destinations reachable through the AS. An AS is identified by an Autonomous System number.

The concept of an AS plays an important role in the Internet routing (see Section 7.1).

Next: 2.2.5 Addressing Architecture

Connected: An Internet Encyclopedia
RFC 1812 - 2.2.4 Autonomous Systems